Lifting jack



lFiled Dec:w 22 1924 2 Smets-.Sheet l im ur Ive.

N" Ilm HIIIIH:` n v @unizar zwen A y G. JENSEN LIFTING JACK Deco 1 Filedr Dec; 22, 1924 2 Sheets-Sheet 2 x YQ, n w

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Patented Dea 1,- 1925.

UNITED STATES PATENTI OFFICE) GUNNAR JENSEN, OF RACINE, WISCONSIN, ASSIGNOR TO WALKE MANUFACTURING COMPANY, OF RACINE, WISCONSIN, A CORPORATION OIWISCONSIN.'

LIFTING J ACK.

p Application filed December 22, 1924. Serial' No. 757,420.

T0 all whom t may concern:

Be it known that I, GUNNAR JENSEN, a subject of the King of Denmark, residing `at Racine, in the county of Racine and State of Visconsin, have invented certain new and useful Improvements in Lifting Jacks, of which the following is a speciiication.

' This invention relates to a lifting'- jack, and more particularly to a' jack designed for use about garages and repair shops for quickly and easily lifting one corner of a "motor car'.

The jack comprises a small portable carriage, -easily shifted into position beneath the car, on which carriage is mounted alift# ing member which may be moved to an extremely low position to get under the aXle of a very low slung car, or under the axle of a car using balloon tires when the tires are flat. The lifting -member is quickly adjusted through a range of initial positions before the lifting operation is commenced. A long, substantially horizontally project- .ing handle, 'having ashort easy stroke, is connected with the carriage and serves to move the carriage into place beneath lthe car as well as t0 elevate and lower the lifting member.

' handle lwill lower or elevate the liftingl member.

' fied, whichis easily operated.

One object ofthe invention is to pro'vide an improved` jack of the type above speciysimple and compact and A further. object is to provide an improved leverage system for increasing the ease rof,

` operatlon of the liftingl member.

Another object is to provide an improved reversing mechanism forthe elevating and lowering4 apparatus.

A further Objectis to provide a simple, pedal-operated releasing mechanism for lthe Numerous othenobjects and advantages of the invention will be ap arent from the fol-4 lowing detailed descriptlon of one approved 5 .-form'of apparatus. l

In the accompanying drawings:

I Fig. 1 is a side elevation gof theicomplete ack, the upper portion of the lifting handle elng partially broken away.

Fig. 2 is an enlarged view of the front portion of the-jack, showing part of the lifting member in central vertical section.

tion so that reciprocation of the hand lever will elevate the lifting member.

Fig. 5 is a view similar to Fig. 4 showing l the reversing mechanism in o rative position so that reciprocation of t e handlever will lower the lifting member and load, f

Fig. 6- is a transverse vertical section taken substantially on the line 6--6 of Fig, 4;

The carriage 1 comprises a pair of similar spaced side castings 2 and 3, between which the lifting mechanism is mounted, the carriage: being mounted at its front end on a pair-"of rollers 4, and at its rear end on 'a pair of small rollers or casters 5. These rollers 4` and 5 have a sufiiciently Wide tread to provide a firm supplort `for the carriage, and at the same time t ey allow the carriage. to

be easily moved into the desired, position benath the car.` These side castings 2 and 3 comprise 'lower longitudinally extending portions 6 which are narrow and normally l quite close 'to the ground,fso that the :Eorf` ward portion of the carria e Amay be'moved ,under loads to be liftedy whlch are practically as near the round as the height of front wheels .4. Adjacent their .rear ends the castings 2 and 3 have upwardly extendinv portions 7 between which the elevating an lowering Jmechanism is mounted.

The lifting member comprises a housin 8 having a vertical cored opening in whie 4is adjustably held a post or bar 9 of square cross-section, having the load-supporting or lifting cap` 10 'at its upper end. The rear-'- face of bar 9 is formed with a rack 11 withl which vcooperates apvl 12, pivoted in the carriage at 13, land held yieldably against the rack by spring 14.. f The engaging teeth the rack bar may be freely lifted past the yieldable pawl, but cannot be lowered within the housing 8 unless the pawl 12 is withdrawn from lts engagementvwith the rack. The projecting ends of a pin 15 inthe lower end of bar 9 travel in slots 16 in the housing 8 to limit the vertical movement of the post or bar 9 within the housing, and prevent the bar from being pulled out of the housing 8. From the lower front portion of housing 8 projects an auxiliary lifting hook 17, which when the housing is in extreme lowered position is lowered beyond the upper surfaces of wheels 4, so that loads under which the wheels 4 may be pushed, can be elevated by means of this hook. Normally the cap 10, at the top of post 9, is used to support the load, and this cap 10 may first be drawn up manually through the housing 8, until it is inapproximately the position to engage under the axle or other load whereby the lifting movement imparted to it from the hand lever, as hereinafter described, may be reduced to a minimum. Load supporting cap 10 will beheld in any position to which it is thus manually lifted by means of the'spring pressed pawl 12.

The housing 8 is supported at the free endsof pairs of parallel swinging links 18 and 19. The rearends of these links 18 and 19 are pivoted at 20 and 21 between the portions 7 of the side castings, while the front ends of the links are pivoted at 22 and 23 to ears formed on the rear face of the housing 8. Links 18 and 19 are of the same length, also the distance between pivots 20 and 21 is the same as the distance between pivots22 and 23. Pivots v20 and 21 lie in one substantially vertical plane, and pivots 22 and 23 in another parallel plane. Consequently, as lthe links 18 and 19 are swun upwardly or downwardl about their pivots 20-and 21, the lifting member comprising housing 8 and bar 9 will alwaysbe vertically positioned. l It will be noted that the pivot 13 for pawl 12 and the pivot 22 for links 18 coincide. A short pedal 24 is also pivoted at 20, along with links 18, in the upper lends of side castings 7. A link 25 connects an upwardly extending portion 26 of pedal 24 with the pawl 12. This link 25 is of the same length and mounted parallel with the links 18 and 19, so that the swinging movement of the lifting member with links v18 and 19 will not affect the normal positions of pedal 24 and pawl 12. However, if at any time, or in any position of the lifting member, the pedal 24 is depressed, pawl 12 will be drawn out of engagement with the rack 11, and lifting bar 9 and load supporting cap 10 will be allowed to drop to their extreme lowered position within the housing 8. v

Preferably integrally formed with the rear end portions of links 19 is a segment 27, concentric with .pivot 21 of the link, and provided on its periphery with an arcuate series of ratchet teeth 28. An operating hand-lever 29, of the form` best shown in Fig. 1, has an upwardlyiturned end portion 30 (see Fig. 3) pivoted at 31 in the carriage frame. Ratchet segment 27 is provided with an arcuate slot32 through which the pivot 3l extends, thus permitting the swinging movement of segment 27, whose radius is greater than the distance between pivots 21 and 31. Mounted on pivot 33 in the yoke 30 of hand lever 29 isa lifting pawl 34. A coiled spring 35 bears at one end 36 `against the base of yoke against a pin 37 projecting from one side of 30 and at its other endv pawl 34, thus normally holding the pawl in engagement with ratchet'teeth 28 on segment 27 A similar pa-wl 38 is mounted on pivot 39 in the carriage., and is held yieldably in engagement with ratchet teeth 28, by means of a coiled spring 40 anchored at one end in the carriage frame and at its other bea-ring against a .pin 41 projecting from one side of pawl 38. Hand lever 29 normally extends substantially horizontally from carriage 1 so as to clear all low hanging portions of the car, and is provided with an upwardly offset handle portion 42 at its free end to facilitate the operation thereof. To operate the jack this handle is reciprocated up and down throu h a short a-rc. The

- teeth on pawls 34 an 38, and ratchet teeth 28, are so inclined that the pawls will yield to allow relative movement of segment 27 thereby, in a clockwise direction, but will not permit relative movement of the segment in a counterclockwise direction, as viewed in Figs. 4 and 5. On the downstroke of hand lever` 29, pawl 34 will positively engage one of the teeth 28 and move the segment 27 forward through a short arc, thus through links 19 elevating the lifting member 8 a short distance. Locking pawl 38 will yield to permit this forward movement of the segment 27 but will engage one of the ratchet teeth 28to prevent retrograde movement thereof and will thus hold the lifting member in elevated position. On the upward stroke of hand lever 29, lifting pawl 34 will yield to ride over the ratchet teeth 28, while the segment 27 and lifting members are being held in their elevated position by locking pawl 38. Each successive reciprocation of the hand lever repeats this cycle of operations to vgradually raise the lifting member to the desired elevated position.

Mechanism now to be described is provided for successively releasing the awls 34 and 38 to permit lowering of the hfting member. The lower end of a reversing member 43 is pivoted at 44 to the lower inlll ner rear side of frame member 2. Reversing member 43 comprises a forwardly extending arm 45, to the front end of which is attached at' 46 a tensioned spring 47 whose other'` end is anchored at 48 to a portion of the carriage frame. This spring 47 normally tends at all times to swing the reversing member 43 toward the left, asviewed in Figs. 4 and 5. The lower forward portion of arm is provided with a curved cam surface 49 adapted in one position of the reversing member, as shown in dotted lines in Fig. 5, to engage with pin 41 on pawl 38 vand move this pawl out of engagement with the ratchet teeth 28. The rear lower surface of arm 45 is provided with a second cam portion 50, adapted at certain times tol engage with the pin 37 on lifting pawl 34, as shown in full lines, Fig. 5, and hold thls pawl out of engagement with ratchet teeth 28. At its upper end the swinglng reversing member 43A is provided with a rearwardly extending arm 51 having a slot 52-in which slidably engages one end portion 53 ofv a link 54 extending toward the operators end of hand lever 29. Pivoted in a' conveniently accessible position on one side of hand lever 29 is a small bell crank 55, the upper arm 56 of which forms a handle and the lower arm 57 having pivotal connections with the other end of link 54. When handle 56 is thrown to the forward position, indicated in Fig. 4, link 54 will bev drawn back so as to engage the end of slot 52 and `hold reversing member 43 against the action of spring'47 out of operative engagement with pins 37 and 41, in all positions of the hand lever 29. This is the adjustment of the parts, as shown in Fig. 4, during the lifting operation, as previously described. It willbe noted that when handle 56 is in this forward position, the pivotal connection of lever 57 and link 54 is moved 'slightly past dead center so f as to lock the parts in this retracted position.

When the jack is to be lowered, handle 56 is swung to the. rear position indicated in Fig. 5. In this position of the control lever 55, link 54 -is moved forwardly so ,as to release the reversing member 43 and permit it to move under the inluence'of spring 47 at all times. With'lever 29 at the top, of its stroke, as shown in full lines in Fig. 5, cam on arm 45 of the reversing" member is engaged with pin 37 on lifting pawl34 holding this pawl outof engagement with the ratchet segment; the segment being held in position at this time by the locking pawl 38.

On the downward stroke of hand ,lever 29, the reversing member 43 will swing forwardly under the iniuence of spring 47, holding pawl 34 out of engagement with the ratchet segment'until the forward cam portion 49 of arm 45 rests upon the pin 41. Upon further downward movement of leger 29, the pin 37 on vpawl 34, will ride forward olf from cam 50 until pawl 34 engages onesupported bythe lifting pawl 34 on handl lever 29. During the rst part of the upward stroke of the hand lever, pawl 34 which is now holding the load, is moved backward, allowing the segment 27 to move with it and slightly lower the load. At this time locking pawl 38 is still held out of engagement with the ratchet segment by cam portion 49 of arm 45. As this upward stroke of the hand lever progresses the pin 37 will engage with the front portion of ca m 50, moving the reversing member 43 back with it, thus lifting the arm 45 and releasing the spring-pressed pawl 38 which will again come into engagement with one of the ratchet teeth 28 and againhold the load. After further upward movement of hand lever 29 the pawl 34, now freed from 'the load, will become disengaged from the teeth 28 and spring 47 will draw the cam 50 downwardly, thus lifting pawl 34 away from the ratchet segment into the full line position shown in Fig. 5. This lcompletes one cycle A of operations, the parts being now in the position they were at the start of the downward stroke, which may now be repeated. Successive reciprocations of the hand lever 29 will slowly lower the lifting member unioo til the load is released. The jack may now be withdrawn from beneath the load, and the` lifting bar 9 quickly restored to its com,- pletely lowered position, by pressing upon the pedal 24. v

In the usual operation of the jack the lifting cap 10 will be in approximately the correct position for engaging under the axle when inthe lowered position shown in Fig. 2. For lifting somewhat higher `positioned parts the cap 10 will first be grasped by hand and lifted to approximately the desired position for engaging under this part. The carriage 1 is then shoved'into position beneath the car, or other part to be lifted, by means of the handle 42. handle 56 is now thrown to its forward position, as shown in Fig. 4, and the handle 42 is swung up and down through a'small arc until the load has been lifted to the desired height. The load will bel held in any positionlto which` ,it may fbe liftedl by locking pawl 38. When it is desired to. llower the "load, the operator simply throws has been completely lowered and supporting cap 10 isl released. The carriage 1 is The small now Withdrawn from beneath the load by the engaging teeth of thepawls and ratchet pullmg on the handle 42.

Obviously the pivot 31 for the end-lever 29 mlght have been made coincident with the pivotal axis 21 of segment 27, in which case the slot 32 in the segment would be unnecessary. However, the constructionl shown is preferable, since this permits a much shorter lever arm between pivot 31 and the axis of lifting pawl 34, than would be the ease if this lever arm were greater than the radius'of segment 27. In this way a much greater mechanical advantage is at" tained, whereby the jack may lbe used to lift heavy loads with very little effort.

The frame and working parts of the jack are all very sturdily built, and the jack is capable of lifting and supporting `very heavy loads in proportion to the 'size of the jack. .When in lowered position, the lifting cap 10 is considerably lower than the uppermost portions of the supporting carriage, and is capable of getting under the.

axle of a very low slung car, or other load. For lifting very lowl lying loads, the hook 17 may be used, which will lift any load under which the rollers 4 can be pushed.

Having described my invention, what I claim is:

1. A lifting jack comprising a horiz0n` tally movable carriage, a vertically movable lifting member, a pair of parallel links, one end of each being pivoted in the carriage and the other ends being pivoted to the lifting member, a ratchet segment formedl on one link concentric with its pivot in the carriage, an operating handle pivoted at one end in the carriage, a spring pressed paWl carried by the handle, and a springpressed locking pawl mounted in the carriage, both pawls cooperating with the ratchet segment, the engaging teeth of the pawls and ratchet beingso shaped 'that the ratchet may move past the pawls in the direction to elevate the lifting member, but retrograde movement is prevented, and a pivoted reversing member mounted in the carriage and Operable from the operators end of the handle which when in one position will be engaged by the pawls to automatically and successively release the pawls to permit the lifting member to .be lowered lstep by step.

2. A lifting jack comprising a horizontally movable carriage, a vertically movable lifting member, a pair of parallel links, one end of leach being pivoted 1n the carriage and the other ends being pivoted to the lifting member, a ratchet segment formed on one link concentric with its ivot in the carriage, an operating handle pivoted at one end in the carriage, a spring pressed pawl carried by the handle, and a spring-pressed locking pawl mounted in the carriage, both pawls cooperating with the ratchet segment,

bemg soshaped that the ratchet may move past the pawls in the direction to elevate the lifting member, but retrograde movement is prevented, and a reversing member vwhich when in one position Will be engaged by the pawls to automatically and successively release the pawls to permit the lifting member to be lowered step by step.

3. .A lifting j ackcomprising a supporting carriage, a vertically movable lifting member, and connections between the carriage and lifting member for elevating and lowering the member comprising a link pivoted at one end to the lifting member and at the other end in the carriage, a ratchet segmentv member mounted in the carriage and adapt-r ed when in one position to be successively engaged by the pawls when the lifting member is being lowered.

4. A lifting jack comprising a supporting carriage, a vertically movablelifting member, and connections between the carriage and lifting member for elevating and lowering the member comprising av link pivoted,

at one end to the lifting member and at the other end in the carriage, a ratchet segment formed on the link concentric with its pivot in the carriage, a hand-lever pivoted at one end in the carriage, aspring-pressed pawl mounted on the hand-lever adjacent its pivoted end and. adapted to engage the ratchet segment, a Vspring-pressed locking pawl mounted in the carriage and also engaging the ratchet segment, a reversing member mounted in the carriage and when in one position remaining out of engagement with the pawls at all times, and when in another position successively engaging the pawls to release them from the ratchet, and means operable from the operators end of the handlever for shifting the position of the reversing member.

5. A lifting jack comprising a supporting carriage, a vertically movable lifting member, and connections between the carriage and lifting member for elevating and lowering the member comprising a link pivoted at one end to the lifting member and at the other end in the carriage, ai ratchet segment formed on the link concentric with its pivot in the carriage, a hand-lever pivoted at one end in the carriage, a spring-pressed pawl mounted on the hand-lever adjacent its pivoted end and adapted to engage the ratchet segment, va spring-pressed Vlocking pawl mounted inthe carriage and also engaging the reversing member successively into engagement with the pawls as the hand-lever is swung through its operating stroke.

6. A lifting jack comprising a supporting carriage, a vertically movable lifting member, and connections between the carriage and lifting member for elevating and 4lowering the member comprising a link pivoted at one end'to the lifting member and at the other end in the carriage, a ratchet segment formed on vthe link concentric with its ypivot in the carriage, there being an arcuate slot in the segment through which the pivot of the hand-lever passes, and a pawl pivoted on the hand-lever adjacent its pivoted end and adapted to cooperate with the ratchet segment.

7. A lifting jack comprising a carriage, a vertically movable lifting member comprising a housing, a rack bar slidable therethrough, a load su-pporting cap at the upper end of the bar, a pawl cooperating with the rack to hold the rack bar in vertically adjusted positions within the housing, a pair of parallel links one end of each being pivoted in the carriage, and the other ends being pivoted to the housing, means for swinging one of the links to raise or lower the lifting member, a pawl-releasing pedal mounted in lche carriage, and a link mounted to move parallel with the lifting links and connecting the pedal with the pawl. i

8. In 'a lifting jack, an elevatin and lowering mechanism comprising a4 pivoted ratchet segment, an operating pawl for the ratchet, and an operating lever carrying the pawl, the short arm of the lever between its fulcrum and the axis of the pawl being less than the radius of thesegment.

9. In. a lifting jack, .an elevating and! lowering mechanism comprising a pivoted ratchet segment, an operating pawl for the ratchet, and an operating lever carrying the pawl, the short arm of the lever between its fulcrum and the axis of the pawl being less than the radius of the segment, and the segment beingprovided with an arcuate slot through which passes the pivot for the lever.

10. In a liftingjack including a supporting frame, an elevating and lowering mechanism comprising a ratchet segment pivoted in the frame, an operating lever pivoted in the frame, a lifting pawl mountedv on the lever, a locking pawl pivoted in the frame, means for normally holding both yieldably in engagement with the ratchet segment, a reversing member mounted in the frame and adapted when in one position to be successivelyengaged by the pawls when the lever is operated to lower the jack, said reversing member having a slotted extension, spring means for normally holding the 'reversing member'in pawl-engaging position, andmeans for holding the reversing member out of pawl-engaging position, when the lever is operated to elevate the jack, said holding means comprising a manually movable, member mounted on the operators end of the operating lever, and a link attached at one end to the movable member and having its other end slidably engaged in the slot of the reversing member.k

11'. A lifting jack including a sup-porting frame, an elevating and lowering mechanism comp-rising a ratchet member, pivoted in Ithe frame, an operating lever pivoted in the frame` a lifting -pawl mounted on the lever, a locking pawl pivoted in the frame, means for normally holding both pawls yieldably in engagement with the ratchet member, a reversing member mounted in the frame and adapted when in one position to be successively engaged by the pawls when the lever is operated to lower the jack, spring means for normally holding the reversing member in pawl-engaging position, and means for holding the reversing member out of pawl-engaging position, when the lever is operated to elevate the jack, said holding.

means comprising a manually movable member on the operators end of the operating lever, and a link connected at its ends to the manually movable member and the reversing member respectively, one of. these connections being slidable so that when the manually movable member is adjusted to the position which brings its link-connection nearer to the reversing member, the reversing member is free to move under the influence of the spring means.

12. In a lifting ack including a supporting frame, an elevating and lowering mechanlsm including a pivoted reversing member, spring means for holding this reversing member yieldably 1n such position that `manipulation of the mechanismwill lower the jack, an operating handle pivoted in the frame, a small manually operable lever ,pivoted on this handle near the free end thereof, and a link connected at its ends with this manually operable lever and the reversing member respectively, one of the connections being slidable so that when the manu.

ing frame, an elevating and lowering mechanism including a pivoted reversing member, sprlng means for holding th1s reverslng member yleldably in such position that ma' nipulation of the mechanism will lower the .member is free to move and a link connected at its ends to the manually operable member and the reversing 10 member, respectively, one of the connections being 'slidable so that in one`adjustment of the manually operable member, the reversing under the influence of the spring means.

` GUN NAR JENSEN. 

